This present invention relates generally to a fastener machine and more particularly to a feeding mechanism for a rivet machine.
Various feeding and setting machines have been used for rivets. Such traditional machines are disclosed in U.S. Pat. No. 6,592,015 entitled “Feeding Heads for Fastening Machines” which issued to Gostylla et al. on Jul. 15, 2003, and U.S. Pat. No. 5,752,305 entitled “Self-Piercing Riveting Method and Apparatus” which issued to Cotterill et al. on May 19, 1998. Both of these patents are incorporated by reference herein.
Another conventional, self-piercing rivet setting machine employs a right angled, T-shaped intersection between a guide track and feed rail paths. This causes a pneumatically driven rivet to undesirably bounce back or ricochet off of the abutting wall of the feed rail (e.g., the top of the T) thereby either jamming the feeding mechanism or being out of position for the subsequent advancement of a pusher shaft. Furthermore, this conventional device employs two linearly moveable plungers, one of which is in the guide track path (e.g., stem of the T) and the other of which is in the trailing branch of the feed rail path. These plungers are hollow and each have a height generally the same as the width. Each plunger is depressed against a compression spring until the plunger directly contacts against a conical face of a set screw. The quick advancing movement of the rivet past each plunger causes each plunger to downwardly move at about 30 feet per second which prematurely fatigues the spring after a number of cycles. Moreover, the air pressure can disadvantageously push the rivet past the plunger in the feed rail prior to advancement of the pusher shaft.
In accordance with the present invention, a fastener machine is provided. In another aspect, a rivet machine employs a rivet feeding mechanism. A further aspect includes a guide located at an intersection between a feed track and a feed rail with the guide having an angular offset orientation relative to both in order to deter ricocheting of the rivet back into the feed track when the rivet enters the feed rail. Moreover, an aspect of the present machine employs a rocker arm pivotable adjacent a feed rail with a finger of the rocker arm being moveable through a hole in a channel to selectively limit movement of the rivet in the channel. In another aspect, a biased plunger has: a longitudinally longer aspect ratio relative to its nominal width to deter misalignment or cocking during movement of the plunger, a stop surface abutting a flange of the plunger to deter fatigue of a biasing member, and/or a beveled hole edge to deter tripping of the rivet when the rivet moves past the hole. Yet another aspect of the rivet machine provides at least a return sensor, an advancing sensor, a rivet feed sensor and a controller. A method of using a rivet machine is additionally provided.
Further advantageous and areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.